Line of position and wind drift plotter



July 11, 1933. P. VAN H. wEEMs LINE OF POSITION AND WIND DRIFT PLOTTER Filed Feb. 8. 193

EENS.

ATTORNEY o at the end of the blade.

l Patented Juiy 1.1,. w33

, rra

PHELIP 'VAN 35114D3351' Wam, mi NETE) STLaTES NAW EGSMIN ME@ WND BRUT PLOTTER application tiled February 3,19%. aerial No. 591,659. (GRANTED UNDER. THE AST @1F MARGH 3,1%3, .41S AMENDED AEEIL 30, 1928; 370 0. G. 757) This invention relatesl to a navigation instrument, and particularly to an instrument for air navigation.

rlhe object of this invention is to provide a simple and convenient device :for showing the' coursev and distance made good by an aircraft and also for plotting the line of position of such craft.

With the above and otherobjects vin view, theinventon consists in the construction, combination and arrangement 'of parte as will be described more fully hereinafter.

ln the drawing:

Fig. 1 is a plan view of my invention; v

Fig. 2 is a side elevational view thereof.

Basically, the only constructions used on a navigation chart are for directions and die-A tances. M present invention isdesigned to facilitate t e plottin of direction and distance for all the pro lems required :for `sea and air navigation. It is intended for use with a universal chart.

The chart 3 having a compass rose 4 is mounted on chart board 13. A. threaded 25 stud 5 on the board extends'through the center of the rose. The instrument consists essentially of .a T-scale having a `calibrated head 6 and a calibrated longitudinally slotted blade 7 with a graduated protractor 8 The instrument is placed with stud extending through slot 9 in the blade and is held .dined in any desired position by thumb nut 10 screwed upon the stud. A calibrated wind velocity arm 1].` has one end pivoted at the center of protractor 8. The scale spacings on the T-scale and the wind arm are equal. A second arm 12, calibrated to the same scale as the wind arm, is pivoted on stud 5 under the thumb o nut.

The course and distance made good are determined as follows: The slot 9 is set to the course steered, say 50, and the air speed is represented to scale by the distance between the center of the protractor 8 and stud 5 which is shown as 8O knots in the drawing. Wind arm 11 is set at an angle to slot 9 equal to the angle between the course steered and the direction of the wind. A rm 12 is then set with its center line intersecting substan-y made good, and the direction of the center line or arrn 12 shows the course made good.

ln plotting a line of position, the slot 9 is turned in the directionof the bearing and the line of position is drawn along head 6 at right angles thereto. The T-scale may be moved toward or away from the assumed position by a distance representing the altitude difference.

It will be understood that the above de- 1. In combination with a chart board having an upstanding stud thereon, a T-scale having a head and a longitudinally slotted blade, both said head and said blade being calibrated to the same scale and the slot in said plate being adapted to receive said stud, a protractor carried by the Jfree end or" said blade, a wind arm calibrated to the said same scale and having one end pivoted at the center osaid protractor, a second arm calibrated 4 to the said scale and having one end pivoted on said stud, and means engageable with said stud to lin said T-scale in position.

2."ln a navigation instrument, a T-scale having a head and a longitudinally slotted blade, both said head 'and said blade being calibrated to the same scale, a protractor carried by the free end of said blade, a wind arm calibrated to the said same scale and having one end pivoted at the center of said protractcr, and a second arm calibrated .to the said scale and adapted to have one end pive on a member slidable in the slot in said PHILIP VAN HORN WEEMS. 

